BSA Challenger - Advice please....

[SRV1]

Many thanks to you all who have taken time to reply with good advice.....I will continue to soak with PlusGas and try out your methods in the next couple of days.

I can't believe the trigger block is so tight to unscrew. It is fairly clean everywhere, no crud or any signs of even slight rust. As pointed out, the bit I am worried about is the hex nut that secures the threaded bush to the trigger block freeing up and allowing it to rotate in the wind so to speak! Big trouble then.

When I started the job yesterday, I had the cylinder vertical in a soft jaw vise, clamped across the axis (the same plane as the pivot bolt) of the breech jaws - not so tight as to distort the jaws as this seemed the more appropriate area to clamp it as it is fairly solid. Expecting the trigger block to be not so tight as this has turned out, when trying to rotate and undo the trigger block, it seemed that it was not a lot of twisting pressure to cause the cylinder to rotate around the breech section by a few degrees. The cylinder and breech end section are two separate component parts originally joined by press fit or other, braze, silver solder? The join between the two is so well finished it is not normally noticeable.

Many thanks again for your suggestions....

[QUIGLEY]

Having read the post again I'm a bit concerned about the integrity of your cylinder.
If it fails at the breech/Jaws end the results could be very serious.
Sorry to alarm you but I think you should get it checked for safeties sake.
Edd.

[thisisdonald]

Just make sure the breech end is pointing in a safe direction in the shed abd not at cash and carry nescafe jars full of assorted nuts and bolts!
Get that trigger block whacked good and proper... try two 6" bits of wood bolted together through the trigger block to give you a bit more leverage when you whack it.. think of it as a hammer multiplier which also protects your trigger!

[SRV1]

Just an update....still raining.

Following welcome advice from replies to my original post, I applied a combination of your suggested ideas. Firstly I cut a small length of 6mm thick flat mild steel bar and bolted to the trigger block through its 1/2" hole. As it happened, I had a short 1/2" bolt that is the pivot for the main stand on my Matchless G3L laying on the bench! The non-threaded portion being a nice fit in the trigger block hole. The bar would be to give some extra leverage for the sharp blows with the hammer (sounds awful I know).....Next, I placed a length of square mild steel stock in the cocking slot to help prevent rotation of the cylinder. Carefully tightening with packing I clamped the cylinder length wise in the V section of the wooden jaws of my old Stanley workbench (built when men were men and sheep were scared). Using a neat flame from my gas torch, heated the end of the cylinder, fairly hot, couple of quick blows with the hammer, nothing....a bit more heat this time, one blow and she was loose - hoping that it was not the hex holding the threaded bush to the trigger block coming loose. Yippee, threads were being exposed, no distortion to the cylinder or cocking slot. Hell, it was tight and no corrosion to the threads on the bush or cylinder, no evidence of thread locking compound either - clean as a whistle. Why oh why so tight?

The Maxigrip lived up to its name and did its job perfectly - a bugger to get off. I had soaked its "sponge" buffers with WD40 several times in the last couple of days, but still a hell of a job to shift even compressing it slightly with a tool I had made. A lot of effort just to get it to move just a few millimetres to clear the slots.

Question: Why oh why with this simple air rifle, the Maxgrip rail and trigger block so difficult to dabble with? Maybe it was just this one?

I had bought the Challenger a couple of years ago at an auction and only test fired it with the intention of stripping it in the future (as of last Sunday!). Little wonder the Challenger graunched a bit on cocking, the spring was in four pieces. Two broken pieces of about two coils each at the piston end and one piece of about two coils at the other end. The buffer washer was, as expected, in bits. It was evident it had a touch of dieselitis....but no bell-end thankfully......

The piston and cylinder considering were very good after cleaning, but, questions after questions may I ask a question again?

The piston head was flopping around like I don't know what. I tapped its roll pin out and removed it. The roll pin is about 2.5mm diameter and fits the piston as it should. But the hole it attaches to on the piston end is about 4.2mm????? Some floating piston!!! Surely this can't be right?

Sorry about questions, questions, I value your input and many thanks for that. I should have put a warning on the header such that due to the length of my post, it should be read after dinner tonight as the chips may be a cold after reading this......

All the best....

[Shed tuner]

the hole for the piston head pin is correct, the idea being that when the piston impacts the end of the cylinder, the buffer compresses, so the piston head moves backwards (pin moves with it).. therefore the hole must be large enough to allow it to move..

I'm rather interested in how you are going to sort the breach jaws / end plug attachment issue... braise / pin ?

[SRV1]

Hi Jon,

Thank you for replying regarding the breech block situation. It is not obvious how this was originally mated with the cylinder, the join is invisible. Through measurements, the two screws that hold the cocking lever bracket go through the cylinder into the solid breech end. I would not expect that to be the design in retaining the breech! It had rotated about <5 degrees, it is back in its original position as the screws line up, but did take some effort.

I am concerned about it such that I will try and hydraulic test it by adapting the trigger block threaded bush as a connection to pressure source (water), making, maybe a sleeve to cover the Maxigrip and cocking slots and doing something to plug the transfer port. Unless I can obtain a used cylinder, but this may be difficult to find....

All the best

[Shed tuner]

There is a mercury cylinder on e8ay right now.. item #201493556292

I'd consider either plug welding or pinning the breach end. Any leakage can be sorted with loctite.

[SRV1]

Thinking more about it, with pressures of 1000psig+ it may not be practical trying to achieve a hydraulic pressure test without getting adequate sealing of the open areas. It will probably be not be easy to ensure total hydraulic (no air) and the fine threads of the cylinder to screw an adaptor into for pressure source may not hold? Maybe too many maybe's. Need to think about it more...a pin through the cylinder and solid breech component could be the way to go and get my wife to put a few tins of pellets through it to see if it holds.......?

[SRV1]

Hi Jon....

I am a bit slow typing, my last reply was too slow to appreciate your last post. Thank you for the heads up regarding the Mercury cylinder up for grabs. Please, does anyone know if the Mercury cylinder would be a direct swap? I don't need the Maxgrip as I shoot open, and after doing battle with it, I am happy to see it go. Is the Mercury breech pivot a pin, or, a bolt like the Challenger? Any other?

Best regards...

[SRV1]

Hi All....

Forgot to apologise to all readers and contributors for this continuing saga. It may run longer than Agatha Christie's "The Mousetrap" in London's West End, I think in its 64th year?

Sorry, sorry, sorry.....

[piggy589]

If the Challenger breech section is similar to the Airsporter of that period it will have been bronze welded to the cylinder.

The very fact you've managed to move it amazes me and would suggest the joint was compromised.

[joffy]

Is it still under warranty

[SRV1]

Many thanks piggy for your information....

[SRV1]

Is it still under warranty

Hi joffy...

Yes, it has a lifetime transferrable guarantee - I am trying to trace the previous owner.....

[joffy]

The maxi grip is a doddle to fit if you have a g cramp and a workmate ....the early mercury's have pins holding the barrel on.

My mercury had one owner before me ...and my airsporter carbine is one owner from new